Image sensors may be semiconductor devices that convert an optical image into electrical signals. Two types of image sensors are charge coupled device (CCD) image sensors and complementary metal oxide silicon (CMOS) image sensors. A unit pixel of a CMOS image sensor may include a photodiode (e.g. to detect light) and a MOS transistor (e.g. to detect electrical signals at each unit pixel), which may result in an electrical image representation.
However, there may be complications in image sensors when the thickness of a protective layer on and/over a top conductive layer is too large, resulting in a light condenser (e.g. a light condenser including a color filter and a micro lens) being too far away from a photodiode, which may result in deteriorated image characteristics.